Superheater or the like



Dec. 29, 1931.

V T. E. MURRAY SUPERHEATEROR THE LIKE Filed May 8, 192 4 5 Sheets-Sheet1N VENTOR fi m/7705: Mil fay A TTO/(NEY Dec. 29, R9311. T. E. MURRAYSUPERHEATER OR THE LIKE Filed y 1924 3 Sheets-Sheet Dec. 29, 1931. T E,M RR Y 1,838,105

SUPERHEATER OR THE LIKE Filed May 8, 1924 3 Sheets-Sheet 3 Patented Dec.29, 1931 NETED vs'rzyrss PATENT OFFICE S THOMAS E. MURRAY, OF BROOKLYN,NEW YORK; JOSEPH BRADLEY MURRAY, THOMAS E. MURRAY, JR, AND JOHN F.MURRAY, EK-ECUTORS OF SAID THOMAS E. MURRAY, DECEASED, ASSIGNORS TQMETROPOLITAN ENGINEERING COMPANY, A CORPORA- TION OI NEW YORKSUPERHEATER OR THE LIKE Application filed m5 8, 1924. Serial No.711,753.

In certain previous applications (Serial No. 642,7 25, filed June 1,1923 and Serial No. 678,443, filed December 4, 1923) for patent, I havedescribed the use for boilers and 811111131 apparatus of tubes with finsor longitudlnal flanges and have described numerous ways in which suchfins could be applied to the tubes.

In the present invention tubes of this character are employed in aspecial arrangement which is particularly adapted to the superheating ofsteam, and is also adapted to heating fluids generally. The accompanymgdrawings illustrate more or less diagrammatically an embodiment of theinvention.

Fig. 1 is a perspective view of part of a superheater with the outershell in section;'

Fig. 2is a cross-section of the same;

Fig. 3 is a longitudinal section through part of a locomotive boilerillustrating an application of the invention to a locomotive superheater7 Fig.4 is a perspective sectional view of a detail of Fig. 3;

Fig. 5 is a similar view illustrating a modification Fig. 6 is alongitudinal section illustrating another modification;

Fig. 7 is a cross-section of Fig. 6 on the line 77.

Fig. 8 is a similar cross-section illustrating a modification in theshape of the fins.-

Referring to the embodiment of the invention illustrated in Fig. 1, theheating gases pass through a tubular shelll which may be of sheet metal.The steam passes through a tube 2 which is arranged in two or moreparallel lengths connected at one end by a bend 3 so that the steampasses through the complete tube from one end to the other.

The straight portions of'the tube are provided with longitudinal flanges3, 4, 5, 6, 7 and 8: on the outside which are'welded at their inneredges to the tube as at 9. 'The flanges may be constructed and fastenedto the tubes in various other ways.

For greater efliciency', I propose to make flanges of different widthsand of such sizes asto occu y as much of the space within the shell 1 asis possible without interfering with each other or to greatlydiminishthe area i slightly modified form, applied to a locomotiveboiler. In the upper part of the boiler shell 10 there is a drum 11 inwhich is located-the inlet end of the pipe 12 which passes through ahead 13 to a steam chest .14. The

usual connections are arranged in this chest so that the steam passesout to superheater tubes 15 and back by. superheater tubes 16 to thechest and thence out through a pipe 17 to the engine. The heating gasespass through the usual boiler tubes 18 which are surrounded by water,these pipes having open ends mounted in the heads 13 and 19. The

superheater tubes are located in the main fire tubes 18. Variousarrangements may be employed, such as that shown in Fig. 1 for example.In Fig. 3 I have shown the admis- Instead of using two separate tubes 15and 16 coupled together as in Fig. 4, a single tube may be used as inFig. 5 formed in two lengths 22 continuously connected by a bend 23 andformed with flanges 24 which also extend continuously around the bend.

Fig. 6 illustrates'a form of the invention in which one of the tubes 25of the superheater is a plain-tube located within the other 26, thelatter being provided with fins 27 and fitting within the boiler tube18. The outer tube 26 of the superheater has itsfree end closed, and theinner tube 25 has its free end open. Either of these tubes may be theinlet branch and the other the outlet branch of the superheater.Assuming that the steam enters through the tube 25 it will pass out ofthe end of the latter into the free end of the surrounding tube 26 andback by way of the annular space between the tube and the pipe 28 whichconducts steam to the entrance.

The area of the several fins should bear a determined relation to thearea (or diameter) of the pipe and to the amount of work that theelement is designed to do, that is,

the quantity of heat which it is to receive and conduct to the steam.The area of the fins should be at least equal to that of the pipe. Forexample, a two inch pipe will have a circumference of a little over sixinches. On such a pipe if there are two fins each should be one andone-half inches wide so that, assuming both faces of the fins exposed,the total area of the fins would be about the same as that of the tube.

For certainty in conducting the heat to the tube, the joint should befully equal to the thickness of the fin. To make sure that this is so,it-is preferable to have the joint actually wider than the averagethickness of I the fin. This may be accomplished as shown in Fig. 8 byusing fins 29 which are tapered in thickness. Thus, in spite of anyaccidental imperfections in the welding, there will be a sufiicient areaof continuous metallic connection to equal the average thickness of thefin. Or the connection might be made in various other Ways.

At the points Where the superheater passes out of one boiler tube andinto the next, it

'is exposed to a considerable extent to the direct radiant heat from thefire bed, and is generally subjected to a more intense heat than in thelengths which are enclosed within the boiler tubes. For the exposedbends, therefore, it is advisable to use a metal with a greaterresistance to oxidation in high temperature, or to coat the tube withone of many coatings which are known to resist rusting crease theheating surface, said'flanges being of varying widths and some at leastof them extending substantially to the outer shell, said outer shellconfining the gases to intimate contact with said flanges.

In witness whereof, I have hereunto signed my name. 1

THOMAS E. MURRAY.

